#include <iostream>
#include <cmath>

using namespace std;
int Max(int x,int y,int z)
{
	int max1 = max(x,y);
	return max1>z ? max1 : z;
 } 
int main()
{
	int a,b,c;
	cin >> a >> b >> c;
	double ret = Max(a,b,c)*1.0 / (Max(a+b,b,c)*Max(a,b,b+c));
	printf("%.3f\n",ret);
	
	return 0;
}
